Wash-draw apparatus



I N VENTOR United States Patent O 4 Claims ABSTRACT OF THE DISCLOSURE A wash-draw apparatus is provided having a plurality of rods mounted between the upper and lower rolls parallel to the direction of travel of the filament bundles. These rods act as guides to the filament bundles and separate them, resulting in decreased lateral shifting, fewer roll Wraps, and increased operating speed.

Field of the invention This invention relates to an improved wash-draw machine for drawing bundles or ropes of dry-spun filaments while passing them through reservoirs of hot wash liquor to extract residual solvent in the filaments. More ,particularly, it relates to a wash-draw machine adapted for simultaneously handling a plurality of filament bundles at high speeds in a uniform manner.

State of the art Dry-spun acrylonitrile polymer filaments usually contain from about to about 40% solvent as they leave the spinning cell. Oriented filaments or fibers having properties suitable for the textile trade `are then provided by drawing the spun filaments .and washing them to remove the residual solvent. A useful wash-draw machine in which the bath comprises a series of cascading reser* voirs is disclosed lby Davis and Palmer in their United States Patent No. 3,124,631. 1n commercial practice, several Abundles or ropes of filaments are generally passed through the wash-draw -machine simultaneously, in sideby-side relationship over and under the rolls conveying them into and out of the various reservoirs. The ropes comprise at least 1,000 filaments each, usually 10,000 filaments or more. The roll speeds at the filament bundle outlet end of the apparatus are higher than the roll speeds at the feed end, so that the filaments are drawn while they are being washed. Preferably, the roll speeds are increased stepwise throughout the machine so that the filaments are drawn in a series of steps while the solvent is extracted.

For maximum productivity, operation of the washdraw machine at high speeds is desired. Unfortunately, at input speeds on the order of 250 y.p.m. and higher, operation of conventional wash-draw apparatus becomes highly unsatisfactory owing to the problem of erratlc, lateral shifting of the ropes. Operation of the machine under these conditions requires greatly increased attention by the operator. Machine shut-down time is much higher due to the occurrence of broken filaments and roll wraps.

The object of the present invention is therefore to provide a wash-draw apparatus adapted for simultaneously handling .a plurality of filament bundles smoothly and uniformly at high speeds.

Statement of the invention In accordance with the present invention, a w-ash-draw apparatus is provided having a plurality of rods mounted between the upper and lower rolls parallel to the direction of travel of the filament bundles. The number of rods provided is sufficient to separate each filament bundle passed 3,421,346 Patented Jan. 14, 1969 lCe through the wash-draw 'apparatus from the filament bundles adjacent to it. The wash-draw machine of this invention can be operated smoothly and uniformly at high speeds to yield bundles of oriented filaments having uniform physical properties and substantially free of any broken filaments.

More particularly, the wash-draw apparatus of the invention comprises a series of rolls rotatably mounted in an elongated vessel with the axes of all the rolls perpendicular to the long axis of the vessel, the rolls being vertically separated so as to provide a set of upper rolls and a set of lower rolls with the lower rolls `being immersed in a liquid for washing and extracting residual solvents from filament bundles passed through the vessel alternately over said upper rolls and under said lower rolls; the rolls at the filament bundle outlet end of said vessel being rotated at a higher peripheral speed th-an the rolls at the inlet end so as to draw the filament bundles as they are passed through the vessel. The wash-draw apparatus is equipped with a plurality of rods mounted between said upper rolls and said lower rolls parallel to the vertical plane passing through the long axis of the vessel.

Preferred embodiment Preferably, the rods are mounted above the level of the liquid in the vessel. Each rod extends over a lower roll and is .attached at one end to a sleeve rotatable about an axis parallel to the axis of said lower roll and is detachably fastened at the other end to a horizontal member parallel to the axis of said roll for movement of the rod through a vertical arc to expose the lower roll.

Drawing The details of the invention will be more clearly api` parent -by reference to the accompanying drawing, which is a perspective view of a portion of the wash-draw machine showing how the rods are mounted in place when the machine is in operation. i

Filament bundles 1 are fed from a supply source into the inlet end of elongated vessel 10 in the direction of the long axis A of the vessel, which is a wash-draw machine of the type shown and described in U.S. Patent 3,124,631 to Davis and Palmer. The filament bundles are passed vbe tween squeeze rolls 2, 3 and 4 into reservoir 5, under lower roll 6 and out of the reservoir and over upper roll 7. The filament bundles are subsequently passed into additional reservoirs and are simultaneously drawn by a series of lupper and lower rolls as shown in U.S. Patent 3,124,631. Rolls 2, 3, 4, 6, 7, and the remaining rolls 'are mounted with axes perpendicular to axis A of the vessel. The liquid in the reservoir is heated by suitable means and is continuously exhausted and replenished by' suitable means, such as those shown inthe patent.

Guide rods 8, mounted yparallel to axis A and perpendicular to the axes of therolls, are attached at one end to sleeves 9 rotatably mounted about shaft 11. At the other end the rods are laid in slots 12 in bar 13 to position the rods in the desired alignment and held in place by a bar 14, fastened by a bolt 15 and wing nut 16. The number of guide rods provided is `sufficient to separate the filament bundles being passed through the wash-draw machine from one another. Additional rods `are easily added, and changes in alignment can be made conveniently. The rods are mounted directly over the lower rolls, but can be swung upwards readily to provide access to the rolls Whenever attention to them is required. Although the rods are shown only over the first lower roll, they may be used over several of the lower rolls, or if desired over all the lower rolls. Use of the rods over the lower rolls at the filament bundle inlet end of the machine is more essential than at the outlet end of the machine from which the drawn filament bundles emerge.

Instead of being mounted on the sleeves in pairs, the rods may be mounted singly or in other suitable fashion.

EXAMPLE Acrylonitrile polymer filaments having a spun denier per filament of 6.2 are drawn in 3 bundles containing approximately 26,000 filaments per bundle at a draw ratio of 1.79 and a final draw roll speed of 400 yards per minute (365 meters per min.) employing the rods shown in the figure. Only one wrap is encountered during a 51/2 hour run in drawing 8,090 lbs. (3,660 kg.) of product.

In a control run wherein conventional ceramic guides having a concave arcuate surface are substituted for the rods, the wash-draw machine can be operated at a final draw roll speed of 200 yards per minute (183 meters per min.). However, four wraps are encountered in drawing 14,780 lbs. (6,700 kg.) of product.

In other runs employing conventional ceramic guides having a concave arcuate surface, attempts are made to operate the wash-draw machine at speeds in excess of 250 yards per minute (229 meters per min.), but at such speeds the machine is inoperable on a commercial basis, with wraps occurring within about two to five minutes of start-up. The advantage of employing the rods of the invention is thus markedly illustrated.

It will be appreciated by those skilled in the art that variations from the details given can be made without departing from the scope of the present invention.

What is claimed is:

1. In a wash-draw apparatus having a series of upper and lower rolls rotatably mounted in an elongated vessel for simultaneously washing and drawingy a plurality of filament bundles, a guide system comprising a plurality 0f rods mounted parallel to the vertical plane passing through the long axis of the said elongated vessel between the said upper and lower rolls whereby the said filament bundles are separated from each other and guided through said wash-draw apparatus.

2. Claim 1 wherein said rods are mounted horizontally and extend over at least one of said lower rolls.

3. Claim 2 wherein said rods are fastened at one end to sleeves rotatable about a shaft mounted horizontally and perpendicularly to the long axis of the said elongated vessel and detachably fastened at the other end to a horizontal member.

4. Claim 3 wherein said rods are mounted in pairs on said sleeves.

References Cited UNITED STATES PATENTS 2,369,809 2/1945 Spangler 68-175 3,180,004 4/1965 Fisher et al. 28-59 FOREIGN PATENTS 437,278 6/ 1948 Italy.

WILLIAM L. PRICE, Primary Examiner. 

